With the new areas accounted for, T-Mobile has now rolled out their 4G HSPA+ network to a total of 15 locations including the previously announced Baltimore, Houston, Kansas City, Las Vegas and Washington D.C. In addition to that, they note network enhancements are also coming to Boston, Chicago, Los Angeles, Minneapolis, the New York metro area, Philadelphia, San Diego and Seattle.

As expected, their wooing of iPhone owners continues as well with the claim that testing has shown that unlocked iPhone 4S devices running over their 4G HSPA+ network have on average, 70% faster download speeds than iPhone 4S devices on AT&T’s network.

Someone put up a website regarding just this sort of thing with T-Mobile and the iphone on their network. It gets updated pretty often with new sightings of the network overhaul and is user submitted. It also covers the entire u.s.